diff options
Diffstat (limited to 'src/3rdparty/proj/PJ_moll.c')
| -rw-r--r-- | src/3rdparty/proj/PJ_moll.c | 62 |
1 files changed, 62 insertions, 0 deletions
diff --git a/src/3rdparty/proj/PJ_moll.c b/src/3rdparty/proj/PJ_moll.c new file mode 100644 index 00000000..ce14cfbc --- /dev/null +++ b/src/3rdparty/proj/PJ_moll.c @@ -0,0 +1,62 @@ +#define PROJ_PARMS__ \ + double C_x, C_y, C_p; +#define PJ_LIB__ +#include <projects.h> +PROJ_HEAD(moll, "Mollweide") "\n\tPCyl., Sph."; +PROJ_HEAD(wag4, "Wagner IV") "\n\tPCyl., Sph."; +PROJ_HEAD(wag5, "Wagner V") "\n\tPCyl., Sph."; +#define MAX_ITER 10 +#define LOOP_TOL 1e-7 +FORWARD(s_forward); /* spheroid */ + double k, V; + int i; + + k = P->C_p * sin(lp.phi); + for (i = MAX_ITER; i ; --i) { + lp.phi -= V = (lp.phi + sin(lp.phi) - k) / + (1. + cos(lp.phi)); + if (fabs(V) < LOOP_TOL) + break; + } + if (!i) + lp.phi = (lp.phi < 0.) ? -HALFPI : HALFPI; + else + lp.phi *= 0.5; + xy.x = P->C_x * lp.lam * cos(lp.phi); + xy.y = P->C_y * sin(lp.phi); + return (xy); +} +INVERSE(s_inverse); /* spheroid */ + double th, s; + + lp.phi = aasin(xy.y / P->C_y); + lp.lam = xy.x / (P->C_x * cos(lp.phi)); + lp.phi += lp.phi; + lp.phi = aasin((lp.phi + sin(lp.phi)) / P->C_p); + return (lp); +} +FREEUP; if (P) pj_dalloc(P); } + static PJ * +setup(PJ *P, double p) { + double r, sp, p2 = p + p; + + P->es = 0; + sp = sin(p); + r = sqrt(TWOPI * sp / (p2 + sin(p2))); + P->C_x = 2. * r / PI; + P->C_y = r / sp; + P->C_p = p2 + sin(p2); + P->inv = s_inverse; + P->fwd = s_forward; + return P; +} +ENTRY0(moll) ENDENTRY(setup(P, HALFPI)) +ENTRY0(wag4) ENDENTRY(setup(P, PI/3.)) +ENTRY0(wag5) + P->es = 0; + P->C_x = 0.90977; + P->C_y = 1.65014; + P->C_p = 3.00896; + P->inv = s_inverse; + P->fwd = s_forward; +ENDENTRY(P) |